We've known for a while now that mobile phones can have an adverse effect on our ability to concentrate, sleep and even socialise. But now new research has uncovered even more damning evidence for smartphone addicts, showing that the devices are actually reducing our intelligence.

Researchers at the University of Texas looked into the 'brain drain' effects of phones, discovering that even so much as being in the same room as the devices is enough to distract users and impair their cognitive ability. Here, we take a closer look at the science behind it all.

The study

In the first of two experiments, 520 people were told to put their smartphones in 'silent' mode and place them either face-down in their desk, in their pocket or bag, or in another room before completing a number of cognitive tests – all of which were designed to measure 'available cognitive capacity'. It was found that the volunteers who left their phones in another room 'significantly outperformed' their peers. The report reads:

"The results of experiment one indicate that the mere presence of participants' own smartphones impaired their performance on tasks that are sensitive to the availability of limited-capacity attentional resources."

For the second experiment, 275 people were told to either put their smartphones in 'silent' mode or switch them off completely, and – similarly to the first test – place them either face-down in their desk, in their pocket or bag, or in another room. In this round, participants were then asked to complete a selection of tasks and were asked a series of questions designed to assess the extent to which they relied on smartphones.

The results showed that those who said they were most dependent on their phones performed worse in tests, but only in instances where handsets were on their desk or in a pocket or bag. Differences between whether the phone was on or off, or placed face-up or face-down seemingly made no difference. The report reads:

"Consistent with the behavioural and self-report results observed in experiment one, the results of experiment two suggest that the mere presence of consumers' own smartphones may adversely affect cognitive functioning even when consumers are not consciously attending to them. Experiment two also provides evidence that these cognitive costs are moderated by individual differences in dependence on these devices."

Further discussion

Ironically, it seems that the more consumers depend on their smartphones, the more they seem to suffer from their presence. "Or, more optimistically," the researchers add, "the more they may stand to benefit from their absence." Commenting on the findings, lead author Dr Adrian Ward said:

"Our smartphones enable—and encourage—constant connection to information, entertainment, and each other. They put the world at our fingertips, and rarely leave our sides. Although these devices have immense potential to improve welfare, their persistent presence may come at a cognitive cost."

He added:

"Even when people are successful at maintaining sustained attention – as when avoiding the temptation to check their phones – the mere presence of these devices reduces available cognitive capability."

If any of this sounds familiar, or you find your phone frustrating but impossible to ignore, then it might be worth considering a digital detox for the sake of your mental health. To make a start, try the following steps...

Leave it out. Try to stop bringing your phone along in instances where you don't really need it. This might mean locking it in your desk drawer while you give that important presentation at work, or leaving it at home when you head out for a walk with your other half.

Sleep it off. Research has shown that having smartphones readily available on our bedside tables adversely affects our sleep and, in turn, our health. If you struggle with those all-important Zzzs, make a habit of leaving your phone downstairs when you go to bed (even if it means investing in a 'real life' alarm clock!).

Get some help. You might find it ironic that there is a smartphone app that helps you reduce your smartphone use, but that's exactly what the The Forest app (£1.49, iTunes) is designed to do. Set the time you want to stay focused for, and in that period a tree will grow from seed to its full leafy magnificence on your screen. Interrupt the screen to check Snapchat, and your tree will die. Motivation or what?

The study was published in the Journal of the Association for Consumer Research.

The materials in this web site are in no way intended to replace the professional medical care, advice, diagnosis or treatment of a doctor. The web site does not have answers to all problems. Answers to specific problems may not apply to everyone. If you notice medical symptoms or feel ill, you should consult your doctor - for further information see our Terms and conditions.